What disappoints you?
The weather? The ending of a movie or book? Your finish in a race? A meal at a restaurant? Politicians; or just people's behavior in general?
How do you react when you're disappointed? If you're like most people you run through a whole mix of emotions. You may feel sadness, regret, anger or bitterness, or even a bit of guilt. The first reactions are to be expected, but why do we sometimes feel guilty? We may wonder if the person or situation that has disappointed us could have been avoided. Was it because of something we did or perhaps didn't do? Is the situation or outcome potentially any fault of ours? We'd be naïve to think that we're completely blameless in some situations. Choosing to eat that heavy dessert after dinner may not have been the wisest decision, so we need to accept some of the blame when we don't feel well later. But people are different, they definitely aren't a dessert that we chose to over-indulge in.
People are complex, and YES, people can make choices. If you feel disappointed by the behavior of someone step back and take an objective look before you start blaming yourself. It's fine to accept some of the blame at times, but I don't think we should automatically think their behavior had anything to do with us. Everyone has the ability to make a choice, but in doing so we should also accept responsibility for any outcomes related. If someone behaves poorly or out of character, maybe there's something else going on. Before we automatically think, 'Oh, I'm sorry. Did I do something to provoke their behavior?' perhaps we should take a deep breath and ask ourselves, 'I wonder what THAT was all about?'
It's normal to be disappointed; in others' behavior as well as our own. Maybe it would be more constructive and beneficial to find out the 'WHY something happened' rather than the 'WHAT happened'. We cannot change the choices people make, only our own. We may never uncover, or even understand the 'why'. We need to cut ourselves some slack. I know, easier said than done. It's hard not to want things to go smoothly or even nicely. It's disappointing when we witness people behaving in selfish or vicious ways. People will always do and say things they regret, but actions AND words have the ability to be hurtful and cannot be taken back. Someone can acknowledge what they've said or done or sometimes what they haven't (but should have). That moment can be crucial and life changing, but it's their moment to take ownership of - not ours.
Be supportive, be a good listener, but never allow yourself to be a doormat.